Biomarker in vivo

Keywords PAHs Bivalves GC-MS GC-MS/MS HPLC-FLD Pollution Biomarkers In vivo experiment Field deployment Biological effects... 

The 1,3-cycloaddition of alkyl azides to terminal alkynes is very slow, but can be catalyzed by Cu(l) (mechanism Straub, 2007)3 This formation of 1,2,3-triazoles, popularized as click reaction , was used by Sharpless and Meldal (both 2002) for the selective and biocompatible ligation of peptides, proteins, and especially for the introduction of biomarkers. In vivo applications in aqueous medium are feasible. The bioresearch community applauded this new tool which aroused fresh enthusiasm in azide chemistry. 

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

Results obtained in in vivo and ex vivo experiments are of various types. Some studies have found positive effects of the consumption of carotenoids or foods containing carotenoids on the markers of in vivo oxidative stress, even in smokers. Other studies demonstrated no effects of carotenoid ingestion on oxidative stress biomarkers of lipid peroxidation. " It should be noted that for studies using food, the activity observed may also be partly due to other antioxidant molecules in the food (phenols, antioxidant vitamins) or to the combination of actions of all the antioxidants in the food. 

Tan, D. X., Manchester, L. C., Reiter, R. J. et al. (1998). A novel melatonin metabolite, cyclic 3-hydroxymelatonin a biomarker of in vivo hydroxyl radical generation. Biochem. Biophys. Res. Comm. 253, 614-20. 

Protein tyrosine residues constitute key targets for peroxynitrite-mediated nitrations. Attack of various free radicals (ONOO-, N02 ) upon tyrosine generates 3-nitrotyrosine, which can be measured immunologically or by GC/MS or HPLC techniques. The detection of 3-nitrotyrosine was considered a biomarker of peroxynitrite action in vivo. Similarly, attack of HOC1 and HOBr on tyrosine generates chlorotyro-sine and bromotyrosine, respectively, both of which are measured most accurately by GC-MS. 

Lambert GH, Hsu CC, Humphrey H, et al. 1992. Cytochrome P4SOIA2 in vivo induction A potential biomarker of polybalogenated biphenyls and their related chemical s effects on the human. Chemosphere 25(1 -2) 197-200. 

Flow cytometry (FCM) is widely used for exploring mechanism of action of compounds that compromise proliferation since it is rapid, accurate and usable for any cellular context [5], In this chapter we want to point out technical and strategic aspects of use of FCM for cell cycle studies of a putative anticancer agent. As an example we used Edotecarin, a topi inhibitor, firstly evaluating proliferation outcome and classical DNA content analysis by propidium iodide, and then since the compound treatment produced cell cycle perturbation difficult to interprete, a two-parametric analysis by 5-bromo-deoxyuridine (BrdU) was applied for separating cell cycle phases. Moreover we put our efforts into identifing specific cell cycle arrest not easily demonstrable by previously described methods, through the use of in vitro kinetics ( pulse and chase ). Finally, in vivo assessment of efficacy and biomarkers modulation after treatment was analyzed. 

Antiproliferative assay, flow cytometry studies, in vivo activities and biomarkers determination represent key tools for profiling the phenotypic response to molecular or pharmacologic perturbation at cellular or tissue levels the study enables therapeutic response irrespective of target activity of topi and taken together, these results suggest that there is a strong potential for edotecarin in clinical [36, 37] development for treatment of human tumors. 

Despite the limitations of the samples, the data did suggest a correlation between elevated baseline pERKl/2 levels and stable disease. The mutational status of B-Raf is another logical candidate for a predictive biomarker, especially since B-Raf mutations have been shown to confer increased sensitivity to MEKl/2 inhibitors using in vitro and in vivo models [ 135] nothing has yet been reported. 

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